GPS 35/36 TracPak TM

GPS SMART ANTENNA

TECHNICAL SPECIFICATION

GARMIN· 1200 E. 151st Street · Olathe, Kansas 66062 ·(913) 397-8200 · (913) 397-8282 FAX

© 1999 GARMIN Corporation, 1200 E. 151st Street, Olathe,KS 66062

All rights reserved. No part of this manual may be reproducedor transmitted in any form or by any means, electronic ormechanical, including photocopying and recording, for anypurpose without the express written permission of GARMIN.

Information in this document is subject to change withoutnotice. GARMIN reserves the right to change or improvetheir products and to make changes in the content withoutobligation to notify any person or organization of suchchanges or improvements.

January, 1999 190-00104-00 Rev. D

CAUTION

The GPS system is operated by the government of theUnited States which is solely responsible for its accuracyand maintenance. Although the GPS 35/36 is a precisionelectronic NAVigation AID (NAVAID), any NAVAID can bemisused or misinterpreted, and therefore become unsafe.Use the GPS 35/36 at your own risk. To reduce the risk,carefully review and understand all aspects of this TechnicalManual before using the GPS 35/36. When in actual use,carefully compare indications from the GPS 35/36 to allavailable navigation sources including the information fromother NAVAIDs, visual sightings, charts, etc. For safety,always resolve any discrepancies before continuingnavigation.

NOTE

This device has been tested and found to comply with thelimits for a Class B digital device, pursuant to Part 15 of theFCC Rules. Operation is subject to the following twoconditions: (1) This device may not cause harmfulinterference, and (2) this device must accept any interferencereceived, including interference that may cause undesiredoperation.

This device generates, uses and can radiate radio frequencyenergy and, if not installed and used in accordance with theinstructions, may cause harmful interference to radiocommunications. However, there is no guarantee thatinterference will not occur in a particular installation. If thisdevice does cause harmful interference to radio or televisionreception, which can be determined by turning the deviceoff and on, you are encouraged to try to correct theinterference by one or more of the following measures:

· Reorient or relocate the receiving antenna.

· Increase the separation between this device and thereceiver.

· Connect this device to an outlet on a different circuitthan that to which the receiver is connected.

· Consult the dealer or an experienced radio/TVtechnician for help.

This device contains no user-serviceable parts. Repairsshould only be performed by an authorized GARMIN servicecenter. Unauthorized repairs or modifications to this devicecould void your warranty and your authority to operate thisdevice under Part 15 regulations.

TABLE OF CONTENTS

1. Introduction 1

1.1 Overview 1

1.2 Features 2

1.3 Technical Specifications 2

1.4 Application 4

2. Operational Characteristics 5

2.1 Self Test 5

2.2 Initialization 5

2.3 Navigation 6

2.4 Satellite Data Collection 7

3. Hardware Interface 9

3.1 Mechanical Dimensions 9

3.2 Mounting Configurations and Options11

3.3 Connection Wiring Description 15

4. Software Interface 17

4.1 NMEA Received Sentences 17

4.2 NMEA Transmitted Sentences 21

4.3 Baud Rate Selection 28

4.4 RTCM Received Data 29

A. Earth Datums A-1

SECTION 1

INTRODUCTION

1.1 OVERVIEW

The GARMIN GPS 35/36 is a complete GPS receiver,including an embedded antenna, designed for a broadspectrum of OEM (Original Equipment Manufacturer) systemapplications. Based on the proven technology found inother GARMIN 12 channel GPS receivers, the GPS 35/36will track up to 12 satellites at a time while providing fasttime-to-first-fix, one second navigation updates and lowpower consumption. Its far reaching capability meets thesensitivity requirements of land navigation as well as thedynamics requirements of high performance aircraft.

The GPS 35/36 design utilizes the latest technology andhigh level circuit integration to achieve superior performancewhile minimizing space and power requirements. All criticalcomponents of the system including the RF/IF receiverhardware and the digital baseband are designed andmanufactured by GARMIN to ensure the quality andcapability of the GPS 35/36. This hardware capabilitycombined with software intelligence makes the GPS 35/36easy to integrate and use.

The GPS 35/36 is designed to withstand rugged operatingconditions and is completely water resistant. The GPS 35/36 is a complete GPS receiver that requires minimaladditional components be supplied by an OEM or systemintegrator. A minimum system must provide the GPS 35/36with a source of power and a clear view of the GPSsatellites. The system may communicate with the GPS 35/36 via a choice of two RS-232 compatible full duplexcommunication channels. Internal memory backup allowsthe GPS 35/36 to retain critical data such as satellite orbitalparameters, last position, date and time. End user interfaces

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such as keyboards and displays are added by the applicationdesigner.

1.2 FEATURES

The GPS 35/36 provides a host of features that make it easyto integrate and use.

1) Full navigation accuracy provided by StandardPositioning Service (SPS)

2) Compact design ideal for applications with minimalspace

3) High performance receiver tracks up to 12 satelliteswhile providing fast first fix and low power consumption

4) Differential capability utilizes real-time RTCMcorrections producing 3-10 meter position accuracy

5) Internal clock and memory are sustained by a memorybackup battery or optional external standby power

6) User initialization is not required

7) Navigation mode (2D or 3D) may be configured bythe user

8) Two communication channels and user selectablebaud rates allow maximum interface capability andflexibility

1.3 TECHNICAL SPECIFICATIONS

Specifications are subject to change without notice.

1.3.1 Physical Characteristics

1) Single construction integrated antenna/receiver.

2) Weight: 4.4 oz, (124.5 g), not including cable

3) Size: 2.230" (w) x 3.796" (l) x 1.047" (h), (56.64 mmx 96.42 mm x 26.60 mm)

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1.3.2 Environmental Characteristics

1) Operating temperature: -30°C to +85°C (internaltemperature)

2) Storage temperature: -40°C to +90°C

1.3.3 Electrical Characteristics

1) Input voltage: 10 to 30 VDC, unregulated.

2) Typically draws 150 mA @ 12 VDC

3) Backup power: Internal 3V Lithium coin cell battery,up to 10 year life

1.3.4 Performance

1) Tracks up to 12 satellites

2) Update rate: 1 second

3) Acquisition time- 15 seconds warm (all data known)- 45 seconds cold (initial position, time and

almanac known, ephemeris unknown)- 5.0 minutes AutoLocateTM (almanac known, initial

position and time unknown)- 5 minutes search the sky (no data known)

4) Position accuracy:Differential GPS (DGPS): 5 meters RMSNon-differential GPS: 15 meters RMS (100 meterswith Selective Availability on)

5) Velocity accuracy: 0.2 m/s RMS steady state (subjectto Selective Availability)

6) Dynamics: 999 knots velocity, 6g dynamics

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1.3.5 Interfaces

1) Dual channel RS-232 compatible with user selectablebaud rate (1200, 2400, 4800, 9600)

2) NMEA 0183 Version 2.0 ASCII output (GPALM,GPGGA, GPGSA, GPGSV, GPRMC, GPVTG,PGRME, PGRMT, PGRMV, PGRMF, LCGLL,LCVTG)

Inputs

- Initial position, date and time (not required)

- Earth datum and differential mode configurationcommand, almanac.

Outputs

- Position, velocity and time

- Receiver and satellite status

- Differential Reference Station ID and RTCM Dataage

- Geometry and error estimates

3) Real-time Differential Correction input (RTCM format)

1.4 APPLICATION

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TYPICAL APPLICATION ARCHITECTURE

SECTION 2

OPERATIONAL CHARACTERISTICS

This section describes the basic operational characteristicsof the GPS 35/36. Additional information regarding inputand output specifications are contained in Section 4.

2.1 SELF TEST

After input power has been applied to the GPS 35/36 andperiodically thereafter, the unit will perform critical self testfunctions and report the results over the output channel(s).The following tests will be performed:

1) RAM check

2) ROM test

3) Receiver test

4) Real-time clock test

5) Oscillator check

In addition to the results of the above tests, the GPS 35/36will report software version information.

2.2 INITIALIZATION

After the initial self test is complete, the GPS 35/36 will beginthe process of satellite acquisition and tracking. Theacquisition process is fully automatic and, under normalcircumstances, will take approximately 45 seconds toachieve a position fix (15 seconds if ephemeris data isknown). After a position fix has been calculated, validposition, velocity and time information will be transmittedover the output channel(s).

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Like all GPS receivers, the GPS 35/36 utilizes initial datasuch as last stored position, date and time as well assatellite orbital data to achieve maximum acquisitionperformance. If significant inaccuracy exists in the initialdata, or if the orbital data is obsolete, it may take 5.0 minutesto achieve a navigation solution. The GPS 35/36 AutolocateTM

feature is capable of automatically determining a navigationsolution without intervention from the host system. However,acquisition performance can be improved if the host systeminitializes the GPS 35/36 following the occurrence of one ormore of the following events:

1) Transportation over distances further than 1500kilometers

2) Failure of the internal memory battery without systemstandby power

3) Stored date/time off by more than 30 minutes

See Section 4 for more information on initializing the GPS35/36.

2.3 NAVIGATION

After the acquisition process is complete, the GPS 35/36will begin sending valid navigation information over itsoutput channels. These data include:

1) Latitude/longitude/altitude

2) Velocity

3) Date/time

4) Error estimates

5) Satellite and receiver status

Normally the GPS 35/36 will select the optimal navigationmode (2D or 3D) based on available satellites and geometryconsiderations. The host system, at its option, may command

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the GPS 35/36 to choose a specific mode of navigation,such as 2D. The following modes are available:

1) 2D exclusively with altitude supplied by the hostsystem (altitude hold mode)

2) 3D exclusively with altitude computed by the GPS 35/36

3) Automatic mode in which the board set determinesthe desired mode based on satellite availability andgeometry considerations

When navigating in the 2D mode (either exclusive orautomatic), the GPS 35/36 utilizes the last computed altitudeor the last altitude supplied by the host system, whicheveris newer. The host system must ensure that the altitudeused for 2D navigation is accurate since the resultingposition error may be as large as the altitude error. SeeSection 4 for more information on altitude control.

The GPS 35/36 will default to automatic differentialcorrections, attempting to apply them to the satellite data, inorder to produce a differential (DGPS) solution. The hostsystem, at its option, may also command the GPS 35/36 tochoose differential only mode. When navigating in thedifferential only mode, the GPS 35/36 will output a positiononly when a differential solution is available.

2.4 SATELLITE DATA COLLECTION

The GPS 35/36 will automatically update satellite orbitaldata as it operates. The intelligence of the GPS 35/36combined with its hardware capability allows these data tobe collected and stored without intervention from the hostsystem. A few key points should be considered regardingthis process:

1) If the GPS 35/36 is not operated for a period of six (6)months or more, the unit will “search the sky” in orderto collect satellite orbital information. This process is

fully automatic and, under normal circumstances, willtake about 5 minutes to achieve a navigation solution.However, the host system should allow the GPS 35/36 to remain on for at least 12.5 minutes after the firstsatellite is acquired (see Section 4 for more informationon status indications).

2) If the internal memory backup battery fails or is notinstalled while the host system power is off and notconnected to standby power, the GPS 35/36 willsearch the sky as described above. The systemdesigner should be aware of the availability of standbypower input to the GPS 35/36 to prevent this situation.

3) If the initial data is significantly inaccurate, the GPS35/36 will perform an operation known asAutoLocateTM. This procedure is fully automatic and,under normal circumstances, will require about 5minutes to calculate a navigation solution.AutoLocateTM, unlike search the sky, does not requirethat the GPS 35/36 continue to operate after a fix hasbeen obtained.

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SECTION 3

HARDWARE INTERFACE

3.1 MECHANICAL DIMENSIONS

The GPS 35 is a complete GPS receiver including antennain a uniquely styled waterproof package.

3.1.1 GPS 35 Dimensions (General Tolerance ±0.50 mm)

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3.1.2 GPS 36 Dimensions (General Tolerance ±0.50 mm)

GPS 35 ONLY

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3.2 MOUNTING CONFIGURATIONS ANDOPTIONS

The following mounting options are available for the GPS35. Mounting is user configurable.

3.2.1 Magnetic Mount

The magnetic mount provides a firm, removable mountingattachment to any ferrous metal surface.

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GPS 35 ONLY

3.2.2 Trunk Lip Mount

The trunk lip mount provides a semi-permanent attachmentto the trunk lip of most automobiles.

GPS 35 ONLY

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3.2.3 Suction Cup Mount

The suction cup bracket provides a removable mountingsurface attached to the inside of a vehicle's windshield.

GPS 35 ONLY

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3.2.4 Flange Mount

The flange mount allows for a permanent installation on aflat surface. This mounting configuration is ideal inapplications in which the far side of the mounting surface isinaccessible.

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3.3 CONNECTION WIRING DESCRIPTION

The GPS 35/36 features a stripped and pre-tinned cableassembly for the greatest connection flexibility. The followingis a functional description of each wire in the cable assembly.

Red: VIN - Unregulated 10 - 30VDC 200 mA(maximum). Typical operating current is150 mA.

Black: GND - Power and Signal Ground

White: TXD1 - First Serial Asynchronous Output.RS-232 compatible electrical specification.This output normally provides serial datawhich is formatted per “NMEA 0183,Version 2.0”. Switchable to 1200, 2400,4800 and 9600 BAUD. This output functionsin parallel with the NMEA output.

Blue: RXD1 - First Serial Asynchronous input.RS-232 compatible with maximum inputvoltage range-25<V <25. This input maybe used to receive serial initialization/configuration data, as specified in Section4.1.

Purple: TXD2 - Second Serial AsynchronousOutput. Electrically identical to TXD1.

Green: RXD2 - Second Serial Asynchronous Input.Electrically identical to RXD1. This inputmay be used to receive serial differentialGPS data formatted per “RTCMRecommended Standards For DifferentialNavstar GPS Service, Version 2.0” (seeSection 4 for more details).

Gray: NMEA-NMEA0183, Version 1.5 electricalspecification compatible serial output.This output is also CMOS compatible with

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a no load voltage swing of 0.2Vdc to 4.8Vdc.This output normally provides ASCIIsentences formatted per “NMEA 0183,Version 2.0”. User selectable baud ratesof 1200, 2400, 4800, and 9600 areavailable. The data output on this pin isidentical to the data output on TXD1.

Yellow: VAUX - Optional External Backup PowerConnection. This is an optional connection.Internal battery capacity is 180 mA hour.Typical current requirement is 65 uA @5VDC. If used, a 4VDC to 30 VDC powersource is required.

SECTION 4

SOFTWARE INTERFACE

The GPS 35/36 interface protocol design is based on theNational Marine Electronics Association’s NMEA 0183 ASCIIinterface specification, which is fully defined in “NMEA0183, Version 2.0” (copies may be obtained from NMEA,P.O. Box 50040, Mobile, AL, 36605, U.S.A.) and the RadioTechnical Commission for Maritime Services’ “RTCMRecommended Standards For Differential Navstar GPSService, Version 2.0, RTCM Special Committee No. 104”(copies may be obtained from RTCM, P.O. Box 19087,Washington, D.C., 20036, U.S.A.). The GPS 35/36 interfaceprotocol, in addition to transmitting navigation informationas defined by NMEA 0183, transmits additional informationusing the convention of GARMIN proprietary sentences.

The following sections describe the data format of eachsentence transmitted and received by the GPS 35/36. Thebaud rate selection and RTCM differential GPS input arealso described.

4.1 NMEA RECEIVED SENTENCES

The subsequent paragraphs define the sentences whichcan be received on RXD1 by the GPS 35/36. Thesesentences are echoed upon receipt to provide handshakingthat the appropriate information was received by the GPS35/36.

hh = 1 byte checksum

4.1.1 Almanac Information (ALM)

$GPALM,<1>,<2>,<3>,<4>,<5>,<6>,<7>,<8>,<9>,<10>,<11>,<12>,<13>,<14>,<15>*hh<CR><LF>

The $GPALM sentence can be used to initialize the sensor

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board's stored almanac information if battery back-up hasfailed.

<1> Total number of ALM sentences to be transmittedby the sensor board during almanac download.This field can be null or any number when sendingalmanac to the sensor board.

<2> Number of current ALM sentence. This field can benull or any number when sendingalmanac to the sensor board.

<3> Satellite PRN number, 01 to 32.<4> GPS week number.<5> SV health, bits 17-24 of each almanac page.<6> Eccentricity<7> Almanac reference time.<8> Inclination angle.<9> Rate of right ascension.<10> Root of semi major axis.<11> Omega, argument of perigee.<12> Longitude of ascension node.<13> Mean anomaly<14> afo clock parameter<15> af1 clock parameter

4.1.2 Initialization Information ($PGRMI GARMINproprietary format)

The $PGRMI sentence provides information used to initializethe GPS 35/36 set position and time used for satelliteacquisition. Receipt of this sentence by the GPS 35/36causes the software to restart the satellite acquisitionprocess. If there are no errors in the sentence, it will beechoed upon receipt. If an error is detected, the echoedPGRMI sentence will contain the current default values.Current PGRMI defaults can also be obtained by sending$PGRMIE, to the board.

$PGRMI,<1>,<2>,<3>,<4>,<5>,<6>,<7>*hh<CR><LF>

<1> Latitude, ddmm.mmm format (leading zeros mustbe transmitted)

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<2> Latitude hemisphere, N or S<3> Longitude, dddmm.mmm format (leading zeros

must be transmitted)<4> Longitude hemisphere, E or W

<5> Current UTC date, ddmmyy format

<6> Current UTC time, hhmmss format

<7> Acquisition Reset, A = begin autolocate, R = restartacquisition

4.1.3 Configuration Information ($PGRMC GARMINproprietary format)

The $PGRMC sentence provides information used toconfigure the GPS 35/36 operation. Configurationparameters are stored in non-volatile memory and retainedbetween power cycles. The GPS 35/36 will echo thissentence upon its receipt if no errors are detected. If anerror is detected, the echoed PGRMC sentence will containthe current default values. Current default values can alsobe obtained by sending $PGRMCE, to the board.

$PGRMC,<1>,<2>,<3>,<4>,<5>,<6>,<7>,<8>,<9><10>,<11>*hh<CR><LF>

<1> Fix mode, A=automatic, 2=2D exclusively (hostsystem must supply altitude), 3=3D exclusively

<2> Altitude above/below mean sea level, -1500.0 to18000.0 meters

<3> Earth datum index. If the user datum index (96) isspecified, fields <4> through <8> must containvalid values. Otherwise, fields <4> through <8>must be null. Refer to Appendix A for a list of earthdatums and the corresponding earth datum index.

<4> User earth datum semi-major axis, 6360000.0 to6380000.0 meters (.001 meters resolution)

<5> User earth datum inverse flattening factor, 285.0 to310.0 (10-9 resolution)

<6> User earth datum delta x earth centered coordinate,-5000.0 to 5000.0 meters (1 meter resolution)

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<7> User earth datum delta y earth centered coordinate,-5000.0 to 5000.0 meters (1 meter resolution)

<8> User earth datum delta z earth centered coordinate,-5000.0 to 5000.0 meters (1 meter resolution)

<9> Differential mode, A = automatic (output DGPSdata when available, non-DGPS otherwise),D = differential exclusively (output only differentialfixes)

<10> NMEA Baud Rate, 1 = 1200, 2 = 2400, 3 = 4800, 4= 9600

<11> Velocity filter, 1 = Automatic filter, 2-255 = Filtertime constant (10 = 10 second filter)

<12> Not used. Null field

All configuration changes take effect after receipt of a validvalue except baud rate which takes effect on the next powercycle or external reset event. Null fields in the configurationsentence indicate not change in the particular configurationparameter.

4.1.4 Output Sentence Enable/Disable ($PGRMOGARMIN proprietary format)

The $PGRMO sentence provides the ability to enable anddisable specific output sentences.

The following sentences are enabled at the factory: GPGSA,GPGSV, GPRMC, PGRME, PGRMT and PGRMV.

$PGRMO,<1>,<2>*hh<CR><LF>

<1> Target sentence description (e.g., PGRMT,GPGSV, etc.)

<2> Target sentence mode, where:0 = disable specified sentence1 = enable specified sentence2 = disable all output sentences3 = enable all output sentences (exceptGPALM)

The following notes apply to the PGRMO input sentence:

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1) If the target sentence mode is ‘2’ (disable all) or ‘3’(enable all), the target sentence description is notchecked for validity. In this case, an empty field isallowed (e.g., $PGRMO,,3), or the mode field maycontain from 1 to 5 characters.

2) If the target sentence mode is ‘0’ (disable) or ‘1’(enable), the target sentence description field mustbe an identifier for one of the sentences being outputby the GPS 35/36.

3) If either the target sentence mode field or the targetsentence description field is not valid, the PGRMOsentence will have no effect.

4) $PGRMO,GPLAM,1 will cause the sensor board totransmit all stored almanac information. All otherNMEA sentence transmission will be temporarilysuspended.

4.2 NMEA TRANSMITTED SENTENCES

The subsequent paragraphs define the sentences whichcan be transmitted on TXD1 by the GPS 35/36.

4.2.1 Sentence Transmission Rate

Sentences are transmitted with respect to the user selectedbaud rate.

The GPS 35/36 will transmit each sentence (except wherenoted in particular transmitted sentence descriptions) at aperiodic rate based on the user selected baud rate and userselected output sentences. The GPS 35/36 will transmit theselected sentences contiguously. The contiguoustransmission starts at a GPS second boundary. The lengthof the transmission can be determined by the followingequation and tables:

total characters to be transmittedLength of transmission =

characters transmitted per sec

Baud characters_transmitted_per_sec

1200 1202400 2404800 4809600 960Sentence max_characters

GPGGA 72GPGSA 73GPGSV 210GPRMC 70GPVTG 34PGRME 36PGRMT 47PGRMV 26PGRMF 79LCGLL 36LCVTG 34

The factory set defaults will result in a once per secondtransmission at the NMEA specification transmission rate of4800 baud.

4.2.2 Transmitted Time

The GPS 35/36 outputs UTC (Coordinated Universal Time)date and time of day in the transmitted sentences. Prior tothe initial position fix, the date and time of day are providedby the on-board clock. After the initial position fix, the dateand time of day are calculated using GPS satelliteinformation.

The GPS 35/36 uses information obtained from the GPSsatellites to add or delete UTC leap seconds and correct thetransmitted date and time of day. The transmitted date andtime of day for leap second correction follow the guidelines

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in “National Institute of Standards and Technology SpecialPublication 432 (Revised 1990)” (for sale by theSuperintendent of Documents, U.S. Government PrintingOffice, Washington, D.C., 20402, U.S.A.).

When a positive leap second is required, the second isinserted beginning at 23h 59m 60s of the last day of a monthand ending at 0h 0m 0s of the first day of the followingmonth. The minute containing the leap second is 61seconds long. The GPS 35/36 would have transmitted thisinformation for the leap second added December 31, 1989as follows:

Date Time

311289 235959311289 235960010190 000000

If a negative leap second should be required, one secondwill be deleted at the end of some UTC month. The minutecontaining the leap second will be only 59 seconds long. Inthis case, the GPS 35/36 will not transmit the time of day 23h59m 59s for the day from which the leap second is removed.

4.2.3 Global Positioning System Almanac Data(ALM)

$GPALM,<1>,<2>,<3>,<4>,<5>,<6>,<7>,<8>,<9>,<10>,<11>,<12>,<13>,<14>,<15>*hh<CR><LF>

Almanac sentences are not normally transmitted. Almanactransmission can be initiated by sending the sensor boarda $PGRMO,GPALM,1 command. Upon receipt of thiscommand, the sensor board will transmit available almanacinformation on GPALM sentences. During the transmissionof almanac sentences other NMEA data output will betemporarily suspended.

<field information> can be found in section 4.1.1.

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4.2.4 Global Positioning System Fix Data (GGA)

$GPGGA,<1>,<2>,<3>,<4>,<5>,<6>,<7>,<8>,<9>,M,<10>,M,<11>,<12>*hh<CR><LF>

<1> UTC time of position fix, hhmmss format<2> Latitude, ddmm.mmmm format (leading zeros will

be transmitted)<3> Latitude hemisphere, N or S<4> Longitude, dddmm.mmmm format (leading zeros

will be transmitted)<5> Longitude hemisphere, E or W<6> GPS quality indication, 0 = fix not available, 1 =

Non-differential GPS fix available, 2 = DifferentialGPS (DGPS) fix available

<7> Number of satellites in use, 00 to 12 (leading zeroswill be transmitted)

<8> Horizontal dilution of precision, 1.0 to 99.9<9> Antenna height above/below mean sea level, -

9999.9 to 99999.9 meters<10> Geoidal height, -999.9 to 9999.9 meters<11> Differential GPS (RTCM-SC104) data age, number

of seconds since last valid RTCM transmission(null if non-DGPS)

<12> Differential Reference Station ID, 0000 to 1023(leading zeros will be transmitted, null if non-DGPS)

4.2.5 GPS DOP and Active Satellites (GSA)

$GPGSA,<1>,<2>,<3>,<3>,<3>,<3>,<3>,<3>,<3>,<3>,<3>,<3>,<3>,<3>,<4>,<5>,<6>*hh<CR><LF>

<1> Mode, M = manual, A = automatic<2> Fix type, 1 = not available, 2 = 2D, 3 = 3D<3> PRN number, 01 to 32, of satellite used in solution,

up to 12 transmitted (leading zeros will betransmitted)

<4> Position dilution of precision, 1.0 to 99.9<5> Horizontal dilution of precision, 1.0 to 99.9<6> Vertical dilution of precision, 1.0 to 99.9

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4.2.6 GPS Satellites in View (GSV)

$GPGSV,<1>,<2>,<3>,<4>,<5>,<6>,<7>,...<4>,<5>,<6>,<7>*hh<CR><LF>

<1> Total number of GSV sentences to be transmitted<2> Number of current GSV sentence<3> Total number of satellites in view, 00 to 12 (leading

zeros will be transmitted)<4> Satellite PRN number, 01 to 32 (leading zeros will

be transmitted)<5> Satellite elevation, 00 to 90 degrees (leading zeros

will be transmitted)<6> Satellite azimuth, 000 to 359 degrees, true (leading

zeros will be transmitted)<7> Signal to noise ratio (C/No) 00 to 99 dB, null when

not tracking (leading zeros will be transmitted)

NOTE: Items <4>,<5>,<6> and <7> repeat for each satellitein view to a maximum of four (4) satellites persentence. Additional satellites in view informationmust be sent in subsequent sentences. Thesefields will be null if unused.

4.2.7 Recommended Minimum Specific GPS/TRANSIT Data (RMC)

$GPRMC,<1>,<2>,<3>,<4>,<5>,<6>,<7>,<8>,<9>,<10>,<11>*hh<CR><LF>

<1> UTC time of position fix, hhmmss format<2> Status, A = Valid position, V = NAV receiver warning<3> Latitude, ddmm.mmmm format (leading zeros will

be transmitted)<4> Latitude hemisphere, N or S<5> Longitude, dddmm.mmmm format (leading zeros

will be transmitted)<6> Longitude hemisphere, E or W<7> Speed over ground, 0.0 to 999.9 knots<8> Course over ground, 000.0 to 359.9 degrees, true

(leading zeros will be transmitted)

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<9> UTC date of position fix, ddmmyy format<10> Magnetic variation, 000.0 to 180.0 degrees (leading

zeros will be transmitted)<11> Magnetic variation direction, E or W (westerly

variation adds to true course)

4.2.8 Track Made Good and Ground Speed with GPSTalker ID (GPVTG)

The GPVTG sentence reports track and velocity informationwith a checksum:

$GPVTG,<1>,T,<2>,M,<3>,N,<4>,K*hh<CR><LF>

<1> True course over ground, 000 to 359 degrees(leading zeros will be transmitted)

<2> Magnetic course over ground, 000 to 359 degrees(leading zeros will be transmitted)

<3> Speed over ground, 00.0 to 99.9 knots (leadingzeros will be transmitted)

<4> Speed over ground, 00.0 to 99.9 kilometers perhour (leading zeros will be transmitted)

4.2.9 Geographic Position with LORAN Talker ID(LCGLL)

The LCGLL sentence reports position information.

$LCGLL,<1>,<2>,<3>,<4>,<5>,<CR><LF>

<1> Latitude, ddmm.mm format (leading zeros will betransmitted)

<2> Latitude hemisphere, N or S<3> Longitude, dddmm.mm format (leading zeros will be

transmitted)<4> Longitude hemisphere, E or W<5> UTC time of position fix, hhmmss format

4.2.10 Track Made Good and Ground Speed withLORAN Talker ID (LCVTG)

The LCVTG sentence reports track and velocity information.

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$LCVTG,<1>,T,<2>,M,<3>,N,<4>,K<CR><LF>

<1> True course over ground, 000 to 359 degrees(leading zeros will be transmitted)

<2> Magnetic course over ground, 000 to 359 degrees(leading zeros will be transmitted)

<3> Speed over ground, 00.0 to 99.9 knots (leadingzeros will be transmitted)

<4> Speed over ground, 00.0 to 99.9 kilometers perhour (leading zeros will be transmitted)

4.2.11 Estimated Error Information ($PGRMEGARMIN proprietary format)

The $PGRME sentence reports estimated position errorinformation.

$PGRME,<1>,M,<2>,M,<3>,M*hh<CR><LF>

<1> Estimated horizontal position error (HPE), 0.0 to9999.9 meters

<2> Estimated vertical position error (VPE), 0.0 to 9999.9meters

<3> Estimated position error (EPE), 0.0 to 9999.9 meters

4.2.12 GPS Fix Data Sentence ($PGRMF GARMINproprietary format)

$PGRMF,<1>,<2>,<3>,<4>,<5>,<6>,<7>,<8>,<9>,<10>,<11>,<12>,<13>,<14>,<15>,*hh<CR><LF>

<1> GPS week number (0-1023)<2> GPS seconds (0-604799)<3> UTC date of position fix, ddmmyy format<4> UTC time of position fix, hhmmss format<5> GPS leap second count<6> Latitude, ddmm.mmmm format (leading zeros will

be transmitted)<7> Latitude hemisphere, N or S

27

<8> Longitude, dddmm.mmmm format (leading zeroswill be transmitted)

<9> Longitude hemisphere, E or W<10> Mode, M = manual, A = automatic<11> Fix type, 0 = no fix, 1 = 2D fix, 2 = 3D fix<12> Speed over ground, 0 to 999 kilometers/hour<13> Course over ground, 0 to 359 degrees, true<14) Position dilution of precision, 0 to 9 (rounded to

nearest integer value)<15> Time dilution of precision, 0 to 9 (rounded to nearest

integer value)

4.2.13 Sensor Status Information ($PGRMT GARMINproprietary format)

The $PGRMT sentence gives information concerning thestatus of the GPS 35/36. This sentence is transmitted onceper minute regardless of the selected baud rate.

$PGRMT,<1>,<2>,<3>,<4>,<5>,<6>,<7>,<8>*hh<CR><LF>

<1> Product, model and software version, this is avariable length field. (NOTE: Since the GPS 35/36utilizes a GPS 25 sensor board, the GPS 25 modeldescription will appear in this field.)

<2> Rom checksum test, P = pass, F = fail<3> Receiver failure discrete, P = pass, F = fail<4> Stored data lost, R = retained, L = lost<5> Real time clock lost, R = retained, L = lost<6> Oscillator drift discrete, P = pass, F = excessive

drift detected<7> Data collection discrete, C = collecting almanac,

null if almanac is current<8> Unit temperature in degrees C<9> Board configuration data, R = retained, L = lost

4.2.14 3D velocity information ($PGRMV GARMINproprietary format)

The $PGRMV sentence reports three-dimensional velocityinformation.

28

$PGRMV,<1>,<2>,<3>,*hh<CR><LF>

<1> True east velocity, -999.9 to 9999.9 meters/second<2> True north velocity, -999.9 to 9999.9 meters/second<3> Up velocity, -999.9 to 9999.9 meters/second

4.3 BAUD RATE SELECTION

Baud rate selection can be performed by sending theappropriate configuration sentence to the GPS 35/36 asdescribed in the NMEA Received Sentences Section,sentence $PGRMC.

4.4 RTCM RECEIVED DATA

Position accuracy of 3-10 meters can be achieved with theGPS 35/36 by using Differential GPS (DGPS) real-timepseudo-range correction data in RTCM SC-104 format.These corrections can be received by the GPS 35/36 onRXD2. Correction data at speeds of 300, 600, 1200, 2400,4800 or 9600 baud can be utilized, as the GPS 35/36automatically detects the incoming baud rate. For details onthe SC-104 format, refer to RTCM Paper 134-89/SC 104-68by the Radio Technical Commission for Maritime Services.

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APPENDIX A

EARTH DATUMS

The following is a list of the GARMIN GPS 35/36 earthdatum indexes and the corresponding earth datum name(including the area of application):

0 ADINDAN - Ethiopia, Mali, Senegal, Sudan1 AFGOOYE - Somalia2 AIN EL ABD 1970 - Bahrain Island, Saudi Arabia3 ANNA 1 ASTRO 1965 - Cocos Island4 ARC 1950 - Botswana, Lesotho, Malawi, Swaziland,

Zaire, Zambia, Zimbabwe5 ARC 1960 - Kenya, Tanzania6 ASCENSION ISLAND 1958 - Ascension Island7 ASTRO BEACON ‘‘E’’ - Iwo Jima Island8 AUSTRALIAN GEODETIC 1966 - Australia,

Tasmania Island9 AUSTRALIAN GEODETIC 1984 - Australia,

Tasmania Island10 ASTRO DOS 71/4 - St. Helena Island11 ASTRONOMIC STATION 1952 - Marcus Island12 ASTRO B4 SOROL ATOLL - Tern Island13 BELLEVUE (IGN) - Efate and Erromango Islands14 BERMUDA 1957 - Bermuda Islands15 BOGOTA OBSERVATORY - Colombia16 CAMPO INCHAUSPE - Argentina17 CANTON ASTRO 1966 - Phoenix Islands18 CAPE CANAVERAL - Florida, Bahama Islands19 CAPE - South Africa20 CARTHAGE - Tunisia21 CHATHAM 1971 - Chatham Island (New Zealand)22 CHUA ASTRO - Paraguay23 CORREGO ALEGRE - Brazil24 DJAKARTA (BATAVIA) - Sumatra Island

(Indonesia)25 DOS 1968 - Gizo Island (New Georgia Islands)

A1

26 EASTER ISLAND 1967 - Easter Island27 EUROPEAN 1950 - Austria, Belgium, Denmark,

Finland, France, Germany, Gibraltar, Greece, Italy,Luxembourg, Netherlands, Norway, Portugal,Spain, Sweden, Switzerland

28 EUROPEAN 1979 - Austria, Finland, Netherlands,Norway, Spain, Sweden, Switzerland

29 FINLAND HAYFORD 1910 - Finland30 GANDAJIKA BASE - Republic of Maldives31 GEODETIC DATUM 1949 - New Zealand32 ORDNANCE SURVEY OF GREAT BRITAIN 1936

- England, Isle of Man, Scotland, Shetland Islands,Wales

33 GUAM 1963 - Guam Island34 GUX 1 ASTRO - Guadalcanal Island35 HJORSEY 1955 - Iceland36 HONG KONG 1963 - Hong Kong37 INDIAN - Bangladesh, India, Nepal38 INDIAN - Thailand, Vietnam39 IRELAND 1965 - Ireland40 ISTS O73 ASTRO 1969 - Diego Garcia41 JOHNSTON ISLAND 1961 - Johnston Island42 KANDAWALA - Sri Lanka43 KERGUELEN ISLAND - Kerguelen Island44 KERTAU 1948 - West Malaysia, Singapore45 L.C. 5 ASTRO - Cayman Brac Island46 LIBERIA 1964 - Liberia47 LUZON - Mindanao Island48 LUZON - Phillippines (excluding Mindanao Island)49 MAHE 1971 - Mahe Island50 MARCO ASTRO - Salvage Islands51 MASSAWA - Eritrea (Ethiopia)52 MERCHICH - Morocco53 MIDWAY ASTRO 1961 - Midway Island54 MINNA - Nigeria55 NORTH AMERICAN 1927 - Alaska56 NORTH AMERICAN 1927 - Bahamas (excluding

San Salvador Island)

A2

57 NORTH AMERICAN 1927 - Central America(Belize, Costa Rica, El Salvador, Guatemala,Honduras, Nicaragua)

58 NORTH AMERICAN 1927 - Canal Zone59 NORTH AMERICAN 1927 - Canada (including

Newfoundland Island)60 NORTH AMERICAN 1927 - Caribbean (Barbados,

Caicos Islands, Cuba, Dominican Republic, GrandCayman, Jamaica, Leeward Islands, Turks Islands)

61 NORTH AMERICAN 1927 - Mean Value (CONUS)62 NORTH AMERICAN 1927 - Cuba63 NORTH AMERICAN 1927 - Greenland (Hayes

Peninsula)64 NORTH AMERICAN 1927 - Mexico65 NORTH AMERICAN 1927 - San Salvador Island66 NORTH AMERICAN 1983 - Alaska, Canada,

Central America, CONUS, Mexico67 NAPARIMA, BWI - Trinidad and Tobago68 NAHRWAN - Masirah Island (Oman)69 NAHRWAN - Saudi Arabia70 NAHRWAN - United Arab Emirates71 OBSERVATORIO 1966 - Corvo and Flores Islands

(Azores)72 OLD EGYPTIAN - Egypt73 OLD HAWAIIAN - Mean Value74 OMAN - Oman75 PICO DE LAS NIEVES - Canary Islands76 PITCAIRN ASTRO 1967 - Pitcairn Island77 PUERTO RICO - Puerto Rico, Virgin Islands78 QATAR NATIONAL - Qatar79 QORNOQ - South Greenland80 REUNION - Mascarene Island81 ROME 1940 - Sardinia Island82 RT 90 - Sweden83 PROVISIONAL SOUTH AMERICAN 1956 - Bolivia,

Chile, Colombia, Ecuador, Guyana, Peru,Venezuela

A3

84 SOUTH AMERICAN 1969 - Argentina, Bolivia,Brazil, Chile, Colombia, Ecuador, Guyana,Paraguay, Peru, Venezuela, Trinidad and Tobago

85 SOUTH ASIA - Singapore86 PROVISIONAL SOUTH CHILEAN 1963 - South

Chile87 SANTO (DOS) - Espirito Santo Island88 SAO BRAZ - Sao Miguel, Santa Maria Islands

(Azores)89 SAPPER HILL 1943 - East Falkland Island90 SCHWARZECK - Namibia91 SOUTHEAST BASE - Porto Santo and Madeira

Islands92 SOUTHWEST BASE - Faial, Graciosa, Pico, Sao

Jorge, and Terceira Islands (Azores)93 TIMBALAI 1948 - Brunei and East Malaysia

(Sarawak and Sabah)94 TOKYO - Japan, Korea, Okinawa95 TRISTAN ASTRO 1968 - Tristan da Cunha96 User defined earth datum97 VITI LEVU 1916 - Viti Levu Island (Fiji Islands)98 WAKE-ENIWETOK 1960 - Marshall Islands99 WORLD GEODETIC SYSTEM 1972

100 WORLD GEODETIC SYSTEM 1984101 ZANDERIJ - Surinam102 CH-1903 - Switzerland103 Hu-Tzu-Shan104 Indonesia 74

GPS 35/36 Rev. 2.08 or later:105 Austria106 Potsdam107 Taiwan (modified Hu-Tzu-Shan)

A4

GARMIN Corporation1200 E. 151st StreetOlathe, KS 660621-800-800-1020(913)397-8200

190-00104-00 Rev. D